Conventionally, as a tool that is attached to a container so as to discharge or jet a liquid contained therein, a trigger sprayer has been widely used.
On principle, this trigger sprayer is provided with a piston and a cylinder, and by moving the piston, pressure is applied to the liquid inside the cylinder so that the liquid is jetted from a nozzle.
The trigger sprayer is classified into several types depending on how to move the piston. One of them includes a trigger sprayer of a type in which, for example, a trigger installed on the front side is pulled rearward by a finger.
When the trigger is grabbed by a hand and moved rearward, the piston is pressed downward in cooperation with the movement of the trigger so that the liquid pressure inside the nozzle is raised.
As a result, the liquid is energetically jetted from the nozzle part.
Moreover, another type thereof has been proposed in which a trigger is disposed on an upper portion of the main body, and by pushing the rear end of the tripper downward, the piston is pushed down in cooperation with the movement so that a pressure is applied to the liquid inside the cylinder (see Patent Literature 1).
The trigger sprayer of this type is provided with an F valve on the upstream side of a passage, and an S valve is installed on the downstream side thereof.
More specifically, the F valve is installed on the passage between a cylinder part and the container, and the S valve is installed on the passage between the cylinder part A and the nozzle part.
A liquid inside the container is once pulled up into the cylinder through the F valve, and the liquid thus pulled up into the cylinder is sent to a nozzle part through the S valve when a pressure is applied thereto, and jetted out.
By the way, as the liquid to be used in the trigger sprayer, soap liquid, milky lotion, etc. and chemical solution are normally used.
These liquids are mostly kept in a completely dissolved state without containing any foreign matter; however, some of them contain fine powder (see Patent Literature 1).
Such a chemical solution containing fine powder causes a problem in which in the container, the fine powder deposits onto the bottom part of the container.
In particular, in the case when the specific gravity of the fine powder is comparatively higher than that of the liquid, this tendency becomes more conspicuous.
When the trigger is activated with the deposition, as it is, being located on the bottom, the liquid having a high density of the fine powder is jetted out.
Of course, when the trigger is activated with no deposition being generated, the liquid having a low density of the fine powder is jetted out.
That is, since the same uniform liquid is not always jetted out, irregularity occurs in the liquid so that the liquid is preferably kept in a diffused state as much as possible.
On the other hand, in the case of a liquid having high density of fine powder, fine powder in a meshed state tends to occur between the valve body of the F valve and the valve mount.
Normally, a gap to be formed into a flow passage of the valve has a structure in which the gap is moved in a direction perpendicular to the flow to be opened; therefore, physically, no big gap cannot be obtained.
For this reason, the liquid containing fine powder causes high resistance when passing through the valve, that is, the gap between the valve body and the valve mount, so that high resistance is caused, resulting in a problem of passage efficiency.
In this manner, in a chemical solution containing fine powder, the conventional F valve has failed to solve the problems from the viewpoint of uniformity of the chemical solution to be jetted or the viewpoint of the passage efficiency of the liquid